Refrigerating apparatus



Jan. 26, 1937. K, M L 2,068,689

REFRIGERATING APPARATUS Original Filed Sept. 30, 1930 I BY INVENT? I wmwyv ATTORN EY Patented Jan. 26, 1937 UNITED STATES REFRIGERATIN G APPARATUS Ralph K. Miller, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation,

a corporation of Delaware Application September 30, 1930, Serial No. 485,346 Renewed October 25, 1933 Claims.

' maintains the desired refrigerating temperature for general refrigerating purposes and which will provide increased cooling automatically when it is desirable, such as when ice cubes are to be frozen or comestibles are to be congealed.

In carrying out this object, it is-a further object to control the refrigerating system normally in response to normal requirements of the system and to control the system to provide increased cooling in direct response to a substance, such as water, which is to .be frozen quickly.

Another and more specific object of the invention is to provide an improved switch for an intermittent compressing refrigerating system having means to operate the compressor continuously when it is desired to congeal comestibles in ice trays in the cooling unit of the system.

Further objects and advantages of the present invention will be'apparent from the follow-' ing description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a sectional view of a switch mechanism illustrating one embodiment of the invention taken on the line 1-1 of Fig. 2 together with a diagrammatic representation of the remaining portions of a compression refrigerating system; and

Fig. 2 is a top view of the switch mechanism shown in Fig. 1. k

Referring to the drawing, there is shown diagrammatically a refrigerating system which, for the purpose of illustrating the invention, is shown as a system of the compressor, condenser, expand er type including a compressor 2| for compressing the refrigerant, preferably sulphur dioxide, and for forwarding it to the condenser 22 where it is liquefied and collected in the receiver 23. A supply conduit 26 supplies refrigerant from a receiver 23 to the cooling unit herein shown as an evaporator 21 where the liquid refrigerant vaporizes because of the absorption of heat and,

is returned to the compressor through the return conduit 28. This evaporator, of course, is placed in a'refrigerator cabinet (not shown) for maintaining the food storage compartment -of the cabinet at a desired refrigerating temperature.

- device as at 43, it is evident that the'bellows will The actuating means for the compressor 2| preferably comprises an electric motor 24 connected by pulley and belt means 25 to the compressor. Pressure responsive control mechanism 29 is connected to the return conduit 28 through the conduit 30 for opening and closing the circult 3| of the electric motor 24 which drives the compressor 2| to provide alternating operative and idleperiods of the compressor according to the pressure and consequently the temperature of the evaporator.

. The pressure responsive means of the control mechanism 29 comprises a hollow metallic bellows 38 which is sealed at the top and which is connected at the bottom by means of the conduit 30 to the return conduit 28 of the refrigerating system. An operating lever 42 pivoted on ears 43 of the elevated platform 40 follows the movements of the bellows 38 by being pivoted thereto by a pin 44. A double lever 4'! straddles the lever 42 and is pivoted thereto by'the pin 52. One end of the lever 41 is connected to one of the switch contacts 45 by a link 48. The cooperating switch contact 46 is mounted on the base 39 of the control mechanism. A- snap action of the contact 45 with respect to the contact 46 is provided by a cam system which includes the hardened steel nose 49,. fastened to the other end of the lever 41; against which a hardened steel roller 50 is biased by a carrier 5| and a spring 52. 30

As the pressure builds up within the flexible metallic bellows38, the latter expands, and since the lever 42 is pivoted to this bellows by the pin 44 and fulcrumed to the supporting frame of the 35 raise the operating lever 42. v

The upward movement of the lever 42 is resisted by a yieldable adjustable system comprising a coil spring carried within an adjustable casing 62 and bearing against a plunger 53 which acts against the extremity 63 of the lever 42. When the pressure decreases and the bellows 38 collapses, the downward movement of the lever will be resisted by a coil spring 54 whose tension may be regulated by nuts 55 carried on a ver- 45 tical threaded rod 56 pivoted to lever 42. A balancing spring 51 adjusted by nuts 58 is used on the opposite side of the base 39 of the device for resisting the tension of the spring 54.

The springs 54 and 57 and the resilient ad- 50 justing system comprising the plunger 53 and an adjustable cap 62 are provided for preferably so adjusting to produce what may be termed normal predetermined adjustment, that is for maintaining a pressure corresponding to a par- 55 for every day operation of the refrigerator in which the system is used. The extremity 63 of the lever 42 bears against the plunger'53 only on the upward action of the lever 42. After lever ,52 begins to descend, the extremity 63 does the action of freezing within the ice trays 65,

'I have provided for modifying the operation of thesystem. In the present embodiment, I control the operation of the control means. The apparatus isusually adjusted at the factory or in' the field by the service man for such normal operation by suitably tensioning the springs 54 and 51 as well as the resilient adjusting system 62 and 53 and in such condition the lever 42 will have its upward and downward movements resisted so that it will open and close the circuit of the driving motor 24 only at the maximum and minimum pressure temperature points for which the tension corresponds.

By interposing a resistance to the downward movement of the lever 42, the operation of the switch contacts will be delayed so that the system will continue operating for alonger period of time, thus prolonging thecooling cycle of the system. Likewise, if the resistance to the descent of the lever 42 is increased, it will require a greater effort on the part of the diaphragm 38 to pull the lever down into contact breaking position (the descent of the lever 42 causing the raising of contact 45 away from the contact 46, thus breaking the circuit).

According to the present invention, automatic thermostatic means are provided for interposing such a resistance. To this end a thermostatic bulb 10 is? interposed between the ice trays 65 in the cooling unit 21. Also an auxiliary bellows H is fastened on a base 39 and positioned so as to contact when-expanded for contact portion 12 on the lower side of the lever 42. The bellows II is normally held in position away from the abutment or contact portion 12 by a pair of springs 13 which have their lower ends connected to the base 39 and their upper ends connected to a cross strip 14 which rests and is fastened to. the top of the bellows H. Therefore, during normal operation, the bellows is ineffective. The thermostatic bulb 10 is connected by a conduit I5 to operate the bellows H. When Warm ice trays filled with substances to be frozen or congealed are inserted in the portion of the cooling unit 21 provided therefor, the heat from the warm ice trays causes a volatile fluid within the thermostatic bulb 10 to expand and flow through conduit 15 and thus expand the bellows II, forcing the lever 42 upwardly so that the contacts 45 and 46 will be closed to start the motor 24. When the contacts as and as are already in closed position, the bellows H will ticular temperature which is ordinarily suitable invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a refrigerating apparatus, a cooling unit having afreezing zone, means for supplying refrigerant to and for withdrawing refrigerant from the cooling unit, control means responsive to pressures of the refrigerant within the cooling 'unit for controlling said last mentioned means,

and means for modifying the operation of the control means including means responsive to the temperature adjacent the freezing zone of the cooling unit.

2. In a refrigerating apparatus, the combination of a closed circuit containing refrigerant and including a compressor, a condenser and a cooling unit, means to drive the compressor, controlling means responsive tothe pressure of refrigerantwithin the cooling unit of the closed circuit for controlling the driving means for normal refrigerating requirements, and means for modifying the operation of the controlling means to provide additional cooling including means responsive to the temperature within a portion of the cooling unit.

3. In a refrigerating apparatus, the combination of a closed circuit including a compressor, a condenser, and a cooling unit containing a plurality of ice trays, driving means for the compressor, controlling means to intermittently 0-perate the driving means in response to the pressure within a portion of the closed circuit, and means for modifying the operation of the con- ,the compressor, a switch having starting and stopping positions for starting and stopping the driving means, said switch having a switch arm,

a bellows responsive to the pressure within 'a portion of the evaporator for operating said arm,

' a second bellows for urging the switch into starting position, and a thermostatic bulb positionedv adjacent the ice trays and connected to the sec- 0nd bellows.

5. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant medium through the evaporator, control means responsive to pressures of the refrigerant medium within the evaporator for automatically controlling the circulating means to maintain said evaporator at a normal predetermined mean temperature, and means for automatically modifying the operation of the control means in response to the temperature of a substance placed in thermal contact with the evaporator to be congealed thereby.

6. Refrigerating apparatus comprising in comculating a refrigerating medium through said evaporator, control means responsive to pressures of the refrigerating medium within the evaporator for automatically controlling the circulating cycles of said first named means including means for adjusting same to normally maintain a predetermined mean temperature of the evaporator, and meansoperable automatically and independent of the adjustable means for modifying the operation of said control means, said last named means being responsive to the temperature of a substance placed in thermal contact with the evaporator to be congealed thereby.

7-. Refrigerating apparatus comprising in combination, an evaporator, mechanism for circulating a refrigerating medium through said evaporator to produce refrigeration therein, control means responsive to pressures of the refrigerating medium within the evaporator for automatically controlling said mechanism for maintaining the temperature of the evaporator within predetermined lirnits, auxiliary means for modifying the action of said control means to change the lower temperature limit of said evaporator while maintaining the upper temperature limit unchanged, said auxiliary means being operated automatically in response to the temperature of a substance placed in thermal contact with the evaporator to be congealed thereby.

8i Refrigerating apparatus'comprising in combination, an evaporator, mechanism for circulating a refrigerating medium through said evaporator to produce refrigeration therein, control means responsive to pressures of the refrigerating medium within the evaporator for automatically controlling said mechanism for maintaining said evaporator at a normal predetermined mean temperature, resistance means on said control means for modifying theaction thereof. to cause the temperature of said evaporator to be lowered below its normal predetermined mean temperature limit, and a thermostat responsive to the tem-,

perature of a substance placed in thermal contact with the evaporator to be congealed, said thermostat having a portion thereof communi cating with said resistance means for automatically rendering said resistance means eifective.

9. In a refrigerating apparatus comprising in combination, a cooling element, means for circulating a refrigerant medium through said element, means for operating said first named means, a switch responsive to pressure of the refrigerating medium 'within the cooling element corresponding to the normal refrigerating requir-ements of the cooling element for controlling operations of said second named means, and means responding automatically to a different refrigerating requirement for changing the action of said switch to modify the operation .of said second named means.

10. In a refrigerating apparatus comprising in combination, an evaporator, means for circulating liquid refrigerant to said evaporator and for withdrawing gaseous refrigerant therefrom, ,means for operating said first named means, a switch responsive to pressure of. the refrigerant within the evaporator corresponding to the normal refrigerating requirements of said evaporator for controlling operations of said second named means, and means for changing the action of said switch to modify the operation of said second named means, said last named means being responsive automatically to the temperature of a substance placed in thermal contact with the evaporator to be cooled.

RALPH K. MILLER. 

